SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08e4866e9606a85680c59daec87585e05d69318ae74ed68d468d03247ec643be' 
  AND token = '68V00YR7sXivK4DrWZ+w2JXvgLU+r2vovBFe+9OMeUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}